Function lookforfunc

** Look for a C function named 'sym' in a dynamically loaded library ** 'path'. ** First, check whether the library is already loaded; if not, try ** to load it. ** Then, if 'sym' is '*', return true (as library has been loaded). ** Otherwise, look for symbol 'sym' in the library and push a ** C function with that symbol. ** Return 0 and 'true' or a function in the stack; in case of ** errors, ret